1. Technical Field
The present invention is directed to notifying a user of an arriving elevator car. More particularly, the present invention is directed to notifying a user as to which elevator car will be responding to a hall call registered by the user, wherein notification occurs a selectable amount of time before the elevator car arrives.
As used herein, notifying a user means energizing, e.g., sounding and/or illuminating, a hall lantern (which usually includes audible and visible alarms) located at or near the elevator car which will be responding to the hall call, thereby indicating to the user which elevator car will be arriving.
2. Background Information
In a building having a plurality of floors, each floor typically has a set of buttons located in the hallway at or near the elevators. These buttons, commonly referred to as hall call buttons, enable users to request elevator car service in a predetermined direction, i.e., up and/or down. Additionally, the interior of an elevator car is generally equipped with a plurality of buttons, commonly referred to as car call buttons, which enable users to request service to specific floors.
In simplified terms, an elevator control system, also referred to in the art as an elevator dispatching system, monitors the status of the hall call buttons at the floors and car call buttons in the elevator cars, assigning elevator cars to the floors in response to hall calls registered at the floors and/or car calls registered in the elevator car.
Several dispatching techniques are known in the art, e.g., dispatching based on static or dynamic sectors, peak-period dispatching (e.g., up-peak, down-peak and noon-time) and dispatching based on bonuses and/or penalties, e.g., the Relative System Response (RSR) methodology proprietary to the assignee of the present invention.
Typically, a user is notified as to which elevator car will be responding to the hall call in one of two ways: immediately or at the last possible moment, i.e., when the elevator car commits to stop at the floor registering the hall call.
In Japan, users typically want to be informed as to which elevator car will be responding to the hall call almost immediately upon hall call registration. In this way, the users can wait near the door of the elevator car which will be responding to the hall call. Thus, in dispatching systems commonly referred to as having instantaneous car assignment, the hall lantern is energized at the time of initial elevator car assignment, which occurs about the time the hall call is registered.
In RSR systems which employ instantaneous car assignment, since the hall lantern is energized at the time of initial elevator car assignment, the system attempts to maintain the integrity of the initial assignment, e.g., by heavily favoring the initial elevator car assignment. In practice, the elevator car which receives the initial assignment is usually the elevator car which responds to the hall call.
In the other types of systems, herein referred to as conventional systems, the hall lantern is energized when the elevator car commits to stop at the floor registering the hall call. As used herein, an elevator car commits when it begins to decelerate so as to come into position and stop at the floor registering the hall call.
The point in time at which the elevator car commits is herein referred to as the stop control point (SCP). The SCP varies since it is dependent upon several factors including the speed of the elevator car, its deceleration rate and its position with respect to the floor. Typically, however, the SCP occurs about 3 to 5 seconds before the elevator car arrives at the floor.
In conventional systems which employ RSR dispatching, the system initially assigns an elevator car to respond to the hall call at the time the hall call is registered. Subsequently, however, the system can reassign a different elevator car to respond to the hall call if the subsequent assignment will be more suitable, that is provide faster response or improved system performance. In order to improve RSR dispatching efficiency, the decision regarding possible reassignment occurs often, e.g., on the order of every second. Since the hall lantern is energized at the time the assigned elevator car commits to the floor, reassignment is transparent to the user.
To improve system efficiency, the elevator car door begins to open before the car fully stops at the floor so that the door is almost completely open when the car stops. Regardless of which dispatching technique is used, the door will typically remain open a fixed time in response to a hall call (e.g., about 4 seconds) or a fixed time in response to a car call (e.g., about 2 seconds).
In conventional systems where notification occurs about 3 to 5 seconds before car arrival, the waiting users have a relatively short amount of time to walk over to and fully board the elevator car before its door begins to close. There are situations where this fixed amount of time might not be satisfactory to accommodate all users wishing to board the elevator car before the door begins to close.
For example, where a rather large number of users are in the hallway, boarding time will increase. Also, if the waiting area where users congregate is relatively large, and a user is stationed relatively far away from the elevator car, this fixed time may not be long enough to accommodate the user. This is especially true in cross-traffic conditions and/or where the user is only partially ambulatory, e.g., due to an injury, a handicap or old age.